Abstract: A system and method for automatically controlling a vehicle speed to a desired cruise speed are disclosed in which an operation of the automatic vehicle speed controlling system is inhibited when any one of the following conditions is established.

Abstract: In order to avoid the formation of smoke and HC when the compression ratio of a swirl chamber type Diesel engine is lowered either by design or by operation in rarified atmospheres, the fuel injector is located on one side of the center axis of the swirl chamber so as to maximize the distance for which the injected fuel can travel before contacting a wall of the chamber and the auxiliary transfer port through which a fraction of the injected fuel is fed to the main combution chamber is arranged so that the axis thereof intersects the axis of the fuel injector and therefore the trajectory along which fuel is injected, at a point defined within the swirl chamber per se and on the opposite side of the center axis with respect to the fuel injector.

Abstract: In order to promote a good flame dispersion within the combustion chamber of a swirl chamber type Diesel engine, a shaped recess formed in the piston crown is arranged to have a trench portion into which the flame from the swirl chamber is injected and mirror image flame dispersion portions on either side of the trench which terminates at the periphery of the piston crown. This arrangement inhibits the formation of secondary flame flows which tend impede desirable patterns within the flame disportion portions and simultaneously enlarges the dispersion area. In addition, careful selection of the dimensions of the transfer port which interconnects the swirl chamber and the main combustion chamber, and the various sections of the shaped recess, promotes further reductions in HC and smoke emissions.

Abstract: In a variable venturi carburetor in which the metering jet portion of fuel changes automatically according to the amount of intake air required to keep the mixture at a constant air-to-fuel ratio at all times, two series-arranged nozzles and an auxiliary fuel passage communicating with the downstream side of the venturi and with the space formed between the two nozzles additionally formed at the fixed venturi portion in such a way that the auxiliary fuel passage can be opened or closed according to engine operating conditions. Therefore, when the auxiliary fuel passage is opened, since fuel is introduced into the venturi through only a single nozzle, a rich mixture is obtained; when the auxiliary fuel passage is closed, since fuel is introduced through two nozzles, a lean mixture is obtained.

Abstract: In a prior-art variable venturi carburetor in which the cross-sectional area of venturi is automatically varied according to the amount of intake air to keep the flow rate of intake air or the vacuum generated at the venturi at a constant level, since the cross section of venturi changes rectangularly, fuel is concentratedly jetted only near the middle portion of the venturi, so that fuel is not uniformly mixed with air passing through the venturi. To overcome these drawbacks, a wall having a reverse trapezoidal recess is provided near the nozzle and further a pair of triangular slots or cutouts are formed near the lower end surface of the suction piston obliquely and symmetrically so as to slidably engage with the wall, with the result that the cross section of the venturi changes trapezoidally and therefore a stable mixture is obtained even when the engine is running at a low speed or being idled.

Abstract: In an exhaust gas recirculation control system in which a fuel injection quantity is determined on the basis of engine speed and engine load, a throttle-closed range is determined on the basis of engine speed and fuel injection quantity. An exhaust gas recirculation control valve has an electromagnetically operable valve actuator, the duty cycle of which is controlled by a control signal. The duty cycle of the valve actuator is variable in accordance with engine operational condition either in or out of the throttle-closed range. An electromagnetically operated actuator is associated with the throttle valve for controlling the operation of the latter. The actuator is operable between a throttle-open position and a throttle-closed position to operate the throttle valve depending on whether the engine operation conditions are within or out of the throttle-closed range.

Abstract: An E.G.R. control system for a diesel engine is disclosed wherein a deterioration in combustion is avoided upon depressing an accelerator pedal for reacceleration after the momentary release of the accelerator pedal. An E.G.R. control unit is responsive to a load indicative signal from a load sensor and a revolution signal from a revolution sensor and generates an engine operating state indicative signal indicating that the engine operates in low load state which requires high E.G.R. flow rate. A monostable circuit, a delay circuit and a logic circuit make up a circuit means for preventing a throttle valve from being closed until the engine keeps operating in the low load state for a time longer than a predetermined time.

Abstract: A throttle valve has or cooperates with a metering wall or walls which function to limit the amount of air permitted to flow past the edge of the throttle valve when it is initially moved from its closed position. The amount of rotation of the throttle valve for a given change of air flow is thus increased enabling the output of a sensor such as a variable resistor to vary sufficiently to enable an accurate indication of the amount of air passing to the engine especially at frequently used relatively low throttle settings.

Abstract: The occurrence times of discharges of a multi-cylinder internal combustion engine of an automotive vehicle having a transmission and sources for deriving signals indicative of: (a) the engine being cranked or operating normally, (b) the transmission being in high or low gear, (c) engine speed, and (d) the values of parameters determining engine load are controlled by a computer responsive to the signals. The computer includes a read only memory having tables for storing signals with values indicative of spark advance and dwell angle as functions of engine load and engine speed for the engine being cranked, operating normally, the transmission being in high and low gear. The computer responds to the signals of the sources for selecting from the tables stored signals having values indicative of spark advance and dwell angle corresponding with the conditions indicated by signals (a), (b), (c) and (d).

Abstract: A fuel injection time is calculated from a flow rate of intake air to an internal combustion engine. A rotational speed of the engine is sensed. A desired recirculation rate of exhaust gas is determined by a central processing unit from the fuel injection time and the rotational speed of the engine using memory which contains a two-dimensional look-up table, each lattice point in the table being defined by axes of fuel injection time and rotational speed of the engine, and each lattice-point containing the value of a desired recirculation rate of exhaust gas.

Abstract: An ignition timing control change-over system for an automotive internal combustion engine which has a spark retarding point in addition to a normal or spark advancing point. The system employs a change-over type relay switch for selectively and independently connecting either the spark advancing or the retarding point to the ignition coil in response to particular operating conditions of the engine. Under certain idling conditions of the engine, the spark retarding point of the distributor is connected to the ignition coil, and at the same time the throttle valve of the engine is opened by a throttle opener for temporarily increasing the engine speed to attain prompt warm-up of the engine and also of the exhaust gases. Unburned hydrocarbons and carbon monoxide contained in the exhaust may be reduced by a considerable degree as a result of this retarded control of the ignition timing under certain idling conditions of the engine.

Abstract: A method of and apparatus for controlling the air-to-fuel ratio of a combustible mixture in an internal combustion engine of the particular type using mixture control means arranged to regulate the air-to-fuel mixture within a predetermined relatively high range for the purpose of enabling an exhaust cleaning catalytic reactor to perform its maximum function, characterized in that the air-to-fuel ratio is reduced, viz., the mixture is enriched during highly loaded operational conditions of the engine by supplying additional fuel to the mixture supply system of the engine, temporarily disabling the mixture control means during such conditions or diluting the exhaust gases during high load conditions of the engine so that the control means is caused to operate in such a manner as to compensate for the reduced concentration of air in the exhaust gases.

Abstract: An intake manifold of a multi-cylinder internal combustion engine is constructed so as to feed a rich air-fuel mixture into certain cylinders, and a lean mixture into the others.